RtlxOemStringToUnicodeSize

UINT64 __fastcall RtlxOemStringToUnicodeSize(const _STRING *OemString){
  UINT64 Length; 
  char *Buffer; 
  UINT64 BytesInUnicodeString; 
  Length = OemString->Length;
  Buffer = OemString->Buffer;
  LODWORD(BytesInUnicodeString) = 0;
  RtlMultiByteToUnicodeSize(&BytesInUnicodeString, Buffer, Length);
  return(unsigned int)(BytesInUnicodeString + 2);
}

Referenced by:

FsRtlNotifyFilterReportChange
RtlOemStringToCountedUnicodeString
RtlOemStringToUnicodeString